1. Field of the Invention
The present invention relates to a sample suction apparatus. In particular it relates to a so-called piercing apparatus for piercing a plug-sealed specimen vessel with a suction needle (piercer) to suck up a sample.
2. Description of Related Art
To suck up a sample such as blood out of a sealed specimen vessel, commonly employed is a method of sucking up the sample by fixing the specimen vessel and then piercing a plug of the specimen vessel with a suction needle in the shape of an injection needle. Specifically, with respect to the specimen vessel tilted to have its plug lower than its bottom, a vessel supporting means is shifted to abut the bottom of the vessel and then a washing bath for washing the suction needle is shifted to abut the plug to fix the specimen vessel. Then the suction needle penetrates the washing bath and pierces the plug to suck up the sample contained in the vessel (see Japanese Examined Utility Model Publication No. HEI 7(1995)-3328).
In a conventional apparatus as described above, two drive sources (air cylinders) are utilized to independently move the vessel supporting means, the washing bath and the suction needle. If the number of the drive source is reduced, size and production costs of the apparatus are reduced and the control thereof is simplified.